Structural health monitoring (SHM) is essential for ensuring the safety and durability of large structures by identifying and mitigating damage risks. Computer vision (CV)-based measurement systems offer advantages over conventional sensors, including broader coverage of inaccessible areas and lower installation costs. This work introduces a novel noncontact CV-based physics-guided framework for measuring structural vibration responses under ambient (stochastic) conditions from its vibration videos, localizing damages associated with mass and stiffness changes, and quantifying their severity. Homography transformation and integration of the speeded-up robust features and Kanade–Lucas–Tomasi tracking algorithms are employed to extract displacement response from vibration video under different camera orientations. Unlike conventional approaches, this study employs principal component analysis as an unsupervised data-driven approach to estimate the optimal system order from displacement responses. State-space matrices’ estimation and potential damage identification are performed using the numerical algorithms for subspace state-space system identification and stochastic damage locating vector approach, respectively. An improved Bayesian inference-based stochastic model updating algorithm is proposed to precisely locate the actual damaged elements of the structure and assess their severity. The proposed methodology is validated on a numerical truss model with simulated damage scenarios and a laboratory-scale wooden truss bridge using sensor-recorded data. The methodology is finally validated on the damage localization for a photo-realistic synthetic truss bridge model from its vibration videos. The improved accuracy of damage severity prediction compared to existing techniques demonstrates the method’s adeptness in precisely detecting structural damage. Furthermore, the methodology showcases its efficacy in locating damage across various severity levels, facilitating its application in real-time SHM.
Banerjee et al. (Wed,) studied this question.